Despite the alarming consequences of immunosuppressive medication noncompliance (MNC), compliance is variable among adult renal transplant patients. Studies in this growing population have likely underestimated MNC, failed to identify patterns of MNC, and not identified the relationship between MNC and serious consequences due to methodological issues. The purpose of this prospective, descriptive, longitudinal study is to examine patterns of MNC in adult renal transplant recipients varying lengths of time since transplant, and the extent to which MNC is associated with the patient outcomes of infection, acute and chronic rejection, graft loss, and death when covariates are controlled (e.g. donor organ source, HLA mismatch, race, recipient sensitization, diagnosis of diabetes mellitus). A secondary aim is to examine the extent to which depression, self-efficacy, and social support predict MNC. Bandura's Social Cognitive theory will serve as a framework for the secondary aim. One-hundred and fifty adult renal transplant recipients will be recruited from a Midwest transplant program. Levels of depression (Beck Depression Inventory), social support (Social Support Appraisals), and medication self-efficacy (Long-Term Medication Behavior Self-Efficacy Scale) will be obtained initially. MNC will be measured for 12 months using the medication event monitoring system (MEMS) 5 TrackCAP. The MEMS records the date and time an electronic cap is removed from each immunosuppression medication vial. The outcome variables of infection, rejection, graft loss, and death will be extracted from the patient records at one year and two years. Ordinary and logistical regression, survival analyses, and graphical methods will be used for analysis of the data. This project is a preliminary step in a research program directed toward evaluating interventions to reduce MNC and, consequently, undesirable patient outcomes. Furthermore, the proposed study addresses the Healthy People 2010 initiative of reducing chronic kidney disease complications, disability, death, and economic costs by optimizing the transplantation treatment method.